Debug- & Release-DLL

Hello !

I've got a DLL-EXE-Probleme:
When using Debug-DLL with a Debug-EXE, everything works fine.
When using Release-DLL with a Release-EXE, everything works fine, too.
But when mixing it up (Release-DLL with Debug-EXE or Debug-EXE with Release-DLL) there are some unexplainable faults. Any ideas ?

Regards

Martin